One of the major dangers for a crane operating from a sea platform for example and lifting from a ship, is that the load, hook or rope may get caught on the ship itself so that as the ship drops away in the trough of a wave its full weight is imposed on the crane causing fracturing of structural elements of the crane. It might be thought that the rope would fracture first, but the strength of a crane hoist rope is calculated to enable safe lifting of the heaviest load for which the crane is intended and this load is of course at a maximum when the hoist rope is at its smallest radius from the central point of the crane. Thus, while at the minimum radius the hoist rope is weaker than the crane structure, and when it is at maximum radius, for example in the case of a crane having an inclined boom when the boom is inclined at its greatest angle to the vertical, the hoist rope may be stronger than the boom, gantry and other structural elements. Thus, there may be a good chance that the rope will remain intact and that structural failure of the crane itself will occur if the maximum safe crane working load is exceeded.